1. Field of the Invention
The present invention relates to a color copying machine or the like, and particularly relates to a method and apparatus for controlling color-tone of a duplicated picture in a color copying machine or the like.
2. Description of the Prior Art
For example, in conventionally generally known color-copying machines for ordinary paper, an image of color toners of cyan, magents, and yellow is transferred onto ordinary paper so as to obtain a color duplicated picture by the mixture of the color toners. In that case, if, for example, a halogen lamp or the like is used as a light source for scanning a surface of an original, the color duplicated material will be less colored with cyan while intensive in red tone, because the light source has a large quantity of light in red component. Alternatively, for example, if a fluorescent lamp or the like having a large quantity of light in blue component is used as a light source, the color duplicated material will be less colored with yellow while intensive in blue tone. Even in the case where the quantity of light emitted from the light source is equal in tone among red, green, and blue components, the reflection factor or transmission factor of an original varies depending on the color of light, for example 70% for red, 20% for green, and 30.about.40% for blue, so that the color duplicated matter becomes unbalanced in color tone, resulting in a problem in color reproducibility.
Recently, a color generating photosensitive medium (hereinafter simply referred to as "a color photosensitive medium") has been known as disclosed, for example, in Japanese Patent Unexamined Publication No. 58-88739. The color photosensitive medium is arranged such that coloring materials of cyan, magenta, and yellow are separately microcapsulized together with photo-setting resin, a photo-intensifier, a photopolymerization initiator, and so on, and the thus prepared microcapsules are mixed with a developer which will cause a developing reaction with the coloring materials in the microcapsules, and the mixture is applied to a surface of a support. When the thus prepared color photosensitive medium is used as a copying sheet of the above-mentioned color copying machine, a duplicated picture is obtained in the following manner. The color photosensitive medium is subject to exposure processing in a predetermined manner such that the cyanic coloring microcapsules on the color photosensitive medium are photo-set at the portion corresponding to the red region on an original, yellow coloring microcapsules are photo-set at the portion corresponding to the blue region on the original, and magenta coloring microcapsules are photo-set at the portion corresponding to the green region on the original. The exposed color photosensitive medium is then pressed by pressing rollers so that the not-set microcapsules on the color photosensitive medium are broken. Thus, a coloring reaction is caused between the coloring materials in the broken microcapsules and the developer such that a red color which is a mixture of magenta and yellow colors is reproduced in the portion corresponding to the red region of the original, a blue color which is a mixture of cyanic and magenta colors is reproduced in the portion corresponding to the blue region of the original, a green color which is a mixture of cyanic and yellow colors is reproduced in the portion corresponding to the green region of the original. Thus, a duplicated picture having colors corresponding to those of the original is obtained. Thus, unlike the conventional case employing means for transferring coloring toners onto an ordinary sheet, the above-mentioned color photosensitive medium is advantageous in that a duplicated picture superior in resolution as well as in clearness can be obtained and the maintenance of the apparatus is easy because no toner is used.
However, even in the case where such a color photosensitive medium is used as a copying sheet, the problem that the color tone of the duplicated picture is made different from that of the original still exists similarly to the case of the color duplication on the conventional PPC, and therefore the problem in color reproducibility is left as it is.